Battery Separator Bonding Layout for Electrolyte Flow and Adhesion
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Solution Overview
Problem
Existing electrochemical devices face challenges in achieving a balance between interfacial adhesion and electrolyte transmission, leading to issues such as uneven electrolyte distribution and reduced cycle performance, particularly in wound batteries.
Innovation Solution
The introduction of a separator with a first bonding layer featuring spaced bonding regions, tilted at specific angles relative to the electrode assembly's sides, and a second bonding layer with aligned regions, creating stable triangular fixing relationships and gaps for electrolyte flow, enhancing deformation resistance and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a continuous bonding layer is used on the separator, then interfacial adhesion between separator and electrode plate is improved, but electrolyte transmission is hindered
Solution Approach 1:
The bonding layer is segmented into discrete bonding regions rather than being continuous. These bonding regions are spaced apart to create gaps that allow electrolyte transmission while maintaining adhesion at the bonding regions. The segmentation principle directly resolves the contradiction by dividing the bonding function into localized zones that preserve both adhesion and fluid transmission.
Solution Approach 2:
Different regions of the separator have different properties: bonding regions provide strong adhesion while non-bonding gap regions provide electrolyte transmission pathways. This local differentiation of quality allows the separator to simultaneously achieve both interfacial adhesion and electrolyte transmission without compromise.
2Ease of manufacture
If bonding regions are aligned parallel to electrode assembly sides, then manufacturing is simplified, but deformation resistance is reduced
Solution Approach 1:
The bonding regions are arranged at an angle (θ2) relative to the electrode assembly side rather than being parallel. This asymmetric angular arrangement creates a geometric configuration that resists deformation forces more effectively while still being manufacturable. The angled orientation distributes stress more favorably across the bonding regions.
Solution Approach 2:
The bonding regions are oriented in a direction that is not parallel to the primary edges of the electrode assembly, introducing an angular dimension to the arrangement. This dimensional change in orientation provides enhanced deformation resistance by creating a more stable geometric configuration that resists shear and bending forces.
3Quantity of substance
If bonding regions are spaced too far apart, then electrolyte transmission is improved, but interfacial adhesion is reduced
Solution Approach 1:
The spacing between bonding regions is optimized within a specific range to balance electrolyte transmission and adhesion. By controlling the distance parameter between bonding regions, the design achieves sufficient gaps for electrolyte flow while maintaining adequate bonding area for strong interfacial adhesion. This parameter optimization resolves the trade-off between transmission and adhesion.
Data Source
AI summary
An electrochemical device includes a housing, an electrode assembly and an electrolytic solution, and the electrode assembly and the electrolytic solution are disposed in the housing. The electrode assembly includes electrode plates and a separator disposed between adjacent electrode plates. The separator includes a porous substrate and a first bonding layer disposed on a surface of the porous substrate. The first bonding layer includes a plurality of first bonding regions spaced apart from each other. A thickness direction of the electrode assembly is defined as a first direction. In the first direction, a circumscribed rectangle of a projection of the electrode assembly possesses a diagonal line and a first side. An angle between the diagonal line and the first side is θ1. An angle between a projection of each of the plurality of first bonding regions and the first side is θ2, where θ1/2≤θ2≤(θ1/2+45°).